Fix test-fs-promises-writefile.js on windows

src/io/PipeWriter.zig

@@ -824,9 +824,11 @@ fn BaseWindowsPipeWriter(
                     .sync_file, .file => |file| {
                         // always cancel the current one
                         file.fs.cancel();
-                        // always use close_fs here because we can have a operation in progress
-                        file.close_fs.data = file;
-                        _ = uv.uv_fs_close(uv.Loop.get(), &file.close_fs, file.file, onFileClose);
+                        if (this.owns_fd) {
+                            // always use close_fs here because we can have a operation in progress
+                            file.close_fs.data = file;
+                            _ = uv.uv_fs_close(uv.Loop.get(), &file.close_fs, file.file, onFileClose);
+                        }
                     },
                     .pipe => |pipe| {
                         pipe.data = pipe;
@@ -1044,7 +1046,6 @@ pub fn WindowsBufferedWriter(
             this.is_done = true;
             if (this.pending_payload_size == 0) {
                 // will auto close when pending stuff get written
-                if (!this.owns_fd) return;
                 this.close();
             }
         }

test/js/bun/util/bun-file.test.ts

@@ -1,6 +1,7 @@
 import { test, expect } from "bun:test";
 import { tmpdirSync } from "harness";
 import { join } from "path";
+import fsPromises from "fs/promises";
 
 test("delete() and stat() should work with unicode paths", async () => {
   const testDir = tmpdirSync();
@@ -21,3 +22,17 @@ test("delete() and stat() should work with unicode paths", async () => {
 
   expect(await Bun.file(filename).exists()).toBe(false);
 });
+
+test("writer.end() should not close the fd if it does not own the fd", async () => {
+  const testDir = tmpdirSync();
+  for (let i = 0; i < 30; i++) {
+    const fileHandle = await fsPromises.open(testDir + "/tmp.txt", "w", 0o666);
+    const fd = fileHandle.fd;
+
+    await Bun.file(fd).writer().end();
+    // @ts-ignore
+    await fsPromises.close(fd);
+    expect(await Bun.file(testDir + "/tmp.txt").text()).toBe("");
+    await Bun.sleep(50);
+  }
+});